Forming cylinders



ug. 8, 1933. E, Hl HUSSEY 1,921,824

FORMING CYLINDERS Filed Feb. 24. 1931 Patented Aug. 8, 1933 n Unirse STATES PATENT orties 10 Claims.

This invention relates to improvements in forming cylinders and the like, and among other objects, aims to provide a cylinder of this character having an improved forming action.

The nature of the invention may be readily understood by reference to one construction embodying the invention and illustrated in the accompanying drawing.

In said drawing:

Fig. 1 is an end elevation, partly in section,

of a forming cylinder and pulp vat; and

Fig. 2 is an enlarged transverse section adjacent the periphery of the cylinder showing details of a dividing strip and other features of the sections adjacent the periphery of the forming cylinder.

The invention is here shown embodied in a suction cylinder for forming a brous web or sheet. Such cylinders are generally divided circumferentially into a plurality of sections so that the application of suction may be limited to certain areas of the cylinder. It is desirable, for reasons which it is not necessary here to explain, to commence formation of the sheet on what may be termed a free cylinder, i. e., one in which the forming action commences merely under the hydrostatic head of the pulp and is therefore uninfluenced by the presence of dividing strips between the various sections of the cylinder. This avoids, among other advantages, the formation of defects or marks in the sheet in the region of the strips or walls which divide the several sections in the cylinder. At a later stage in the process suction is applied and continued until the region where the sheet leaves the cylinder.

The illustrative apparatus comprises a cylinder 10, generally of ordinary construction, having a plurality of sections or compartments 11 formed by dividing strips 12. Water is drawn off from the respective sections by pipes or conduits 13 which communicate with the respective sections through the inner Walls 14 thereof and lead outwardly parallel to the cylinder axis to a suction regulating valve (of the usual design) adjacent the end of the cylinder, which valve, of course, serves not only to apply and cut off suction but also to open the sections to atmospheric or other pressure at the proper time. Where a long cylinder is employed two pipes may communicate with each section, generally adjacent the ends thereof.

Intermediate the dividing strips are wire supporting bars 15 of wood or other appropriate material which extend longitudinally of the drum and are provided with ribs 16 for engaging the winding wires 17. The bars have spaced transverse saw kerfs 18 extending from the bottom to the base of the groove between the ribs 16 to permit water to drain away freely. The face wire or screen 19 upon which the brous web is formed is supported upon-the winding wires.

The dividing strips are constructed andarranged to permit a controlled communication between sections. The control of this communication is effected in the present case by a valve member in the form of a longitudinally extending rod or bar 2i) of circular section (preferably rounded at its ends and a trifle shorter than the distance between the ends of the forming cylinder) which controls a series of openings or ports 21 and 22 extending longitudinally of the dividing strip. The control of the ports 2l and 22 by the rod is effected in the present case by the rotation of the cylinder; and the rod is confined in its movements by a longitudinally extending cage provided by the forked ends 23 of the dividing strip which enclose a space 24, somewhat larger in diameter than the rod, in which the rod may roll during the rotation of the cylinder.

lThus when the successive division, strips reach thetop of the cylinder the rod 20 lies approximately in the position indicated in full lines in Fig. 2 and when they approach the bottom of the cylinder, the rod occupies the position indicated in dotted lines in Fig. 2. The extremities 25 of the dividing strip are here shown converging and are spaced and tapered to a shape approximating that of the ribs 16. The dividing strip being preferably made of metal, the winding wires 17 may advantageously be soldered to the extremities 25 before the placing of the face wire 19 thereon.

The slope of the surfacer26 adjacent the ports 2l and 22 of the enclosure and the circumferential location of the ports are designed to cause the rod to seat upon and close the ports 21 and 22 at'the desired point in the rotation of the cylinder and also to open such ports in the de` sired region. For a cylinder of about 8 feet in diameter the total diameter of the rod is approximately 11A; inches and the transverse width of the space 24 is something over 3 inches. To effect a tight closing of the ports 21 and 22, the rod 20 is advantageously provided with a facing of soft rubber, in this case about 1A; inch in thickness. The ports 21 and 22 are shown as slots or perforations about 1/4 inch wide. The number of the perforations or slots should obviously be adequate to carry away the Water.

To secure the application of suction above referred to, the valve controlling the forming cylinder may be designed so that suction is applied only as the successive pipes 13 reach the region 28 at the bottom of the vat 29. Therefore, suction can be communicated to the successive sections moving down into the pulp only through successive ports 21 and 22 (which are in communication by reason of the fact that the valve rod has rolled away from the ports); but since all water must drain through the successive sections which lie between the section 30 (just entering the pulp) to the bottom section, the vacuum is successively reduced in passing through the sections,with the result that the section entering the pulp is subjected to practically no suction. Thus the initial forming surface of the cylinder is free and the pressure conditions in the wire at the division strip are just the same as in the section itself. Thus the condition of the web formed over the end of the dividing strip will be exactly the same as that on the wire adjacent thereto, and the objectionable mark usually found on the web in register with the division strip will be eliminated. As the cylinder moves down into the pulp the suction gradually increases because the number of sections and ports through which it must be communicated gradually becomes less.

In the present case the suction controlling valve is designed to subject each section passing the bottom point directly to the vacuum through the respective pipes 13. As the formed web leaves the pulp, the slope of the surface 26 at this point ,is such that the rod lies over the series of ports 22 (and presently also over ports 2l) thus closing communication between the sections when they have left the pulp in the vat. At the same time the suction control valve is arranged to cut off suction from the section leaving the vat. As soon as the suction has been cut oil, the passage of air through the formed web reduces the vacuum in the section very considerably. Upon further movement of the section, the control valve opens the section to atmosphere, and then the formed Web is ready to leave the wire. The slope of the surface 26 on the opposite side of the enclosure is designed so that just before a given section enters the pulp the rod valve rolls away to uncover the ports 2O and 21, thus leaving the wire over this section as well as that in register with the division strip in a free condition.

As stated above, the slope of the surface of the enclosure 24 adjacent the ports 20 and 21 and the spacing of the portsmay be designed to give a somewhat diiferent timing for the seating and unseating of the valve if a different operation be desired.

Obviously, the invention is not limited to the details of kthe illustrative construction since these may be variously modified, moreover, it is not indispensable that all featuresoi the invention be used conjointly since various features may advantageously be used in different combinations and sub-combinations.

Having described my invention, I claim:

l. The combination in a sectioned forming cylinder comprising a section dividing strip having ports therein to permit communication between adjacent sections, a valveV member j ing ports therein to permit communication between adjacent sections, a valve cage associated with said ports, and a valve member freely movable in said cage, said ports being located so as to be closed by said valve at the point where it is desired to close communication between adjacent sections.

3. The combination in a sectioned forming cylinder comprising a section dividing strip -embodying a longitudinal enclosure having ports therein providing communication between adjacent sections, and a rotary valve member freely movable around said enclosure during the rotation of the cylinder, said ports being positioned between adjacent sections, and a valve roll adapted to roll in said enclosure upon rotation of said cylinder to control said ports.

5. A suction cylinder of the character described comprising in combination a forming wire, a plurality of dividing strips for dividing said cylinder into sections for the application of suction to certain regions of said wire, said strips having ports therein providing communication between adjacent sections, and valve means operated by the rotation of said cylinder for maintaining said sections in communication during the initial web forming operations, whereby the web is initially formed by hydrostatic head.

6. A suction cylinder of the character described comprising in combination a forming wire, a plurality of dividing strips for dividing said cylinder into sections for the application of suction to certain regions of said wire, said strips having ports therein providing communicationl between adjacent sections, and valve means operated by the rotation of said cylinder for closing communication between said sections just before the formed web leaves the cylinder.

7. Web forming apparatus comprising in combination a vat having therein a rotary forming cylinder, dividing strips for dividing the cylinder into a plurality of sections for the application of suction, each dividing strip being provided with a forked end forming spaced narrow ribs engaging said wire, and having ports connecting the space between said ribs with an adjacent section, whereby` the wire opposite said dividing strips is subjected to the same pressure conditions as the wire opposite the adjacent section.

S. Web forming apparatus comprising in combination a vat having therein a rotary forming cylinder, dividing strips for dividing the cylinder into a plurality of sections for the application of suction, each dividing strip being provided with a forked end forming spaced narrow ribs engaging said wire and having ports connecting the space between said ribs with both adjacent sections whereby the wire opposite said strips is subjected to the same pressure condition as that opposite the adjacent sections, and means for closing said ports when it is desired to change the pressure conditions between adjacent sections.

9. Web forming apparatus of the character described comprising in combination a pulp vat,la rotating forming cylinder operating therein and ico a rotating forming cylinder operating therein and having a plurality of separate compartments around its periphery, means for applying suction to each compartment as it approaches the bottoml of the Vat, and means for successively reducing the degree of suction on the following compartments, whereby the suction on said compartments is gradually increased as the compartments advance in the pulp.

ERWIN H. HUSSEY. 

